Influence of Renal Function and Diet on Acid-Base Status in Chronic Kidney Disease Patients

Objective We investigated the influence of potential renal acid load (PRAL) and renal function on the degree of metabolic acidosis in patients with chronic kidney disease (CKD). Design This was a cross-sectional study. Setting This study was conducted at the Nephrology Outpatient Division of the Hospital Universitário Clementino Fraga Filho (Rio de Janeiro, Brazil). Patients Thirty CKD patients undergoing conservative treatment were divided according to plasma HCO3− values into acidotic (HCO3− ≤22 mM, n = 15) and nonacidotic (HCO3− >22 mM, n = 15). Main Outcome Measure Biochemical, nutritional, and anthropometric parameters and PRAL were measured. Results The mean of plasma HCO3− values was 17.7 ± 2.8 mM in the acidotic group, and 25.1 ± 2.2 mM in the nonacidotic group. There was no significant difference in mean PRAL values between the acidotic (9.8 ± 6.4 mEq/day) and nonacidotic (12.7 ± 10.0 mEq/day) groups, but there was a significant correlation between plasma HCO3− and creatinine clearance ( r = 0.78, P < .0001). Based on the receiver operating characteristic curve, the level of creatinine clearance to begin detection of acidosis was 31.8 mL/min, with a sensitivity and specificity of 86.7%. Conclusion The acid-base status of this group of CKD patients undergoing conservative treatment was mainly determined by degree of renal insufficiency rather than diet.